usnic: make v1.10 and v2.0 fit in version checking scheme

v1.10 is now in the same compatibility level as v1.7/v1.8 (there
is/will be no v1.9 series).  v2.0 now takes over for what used to be
called v1.9.

opal/mca/btl/usnic/btl_usnic_compat.h

@@ -15,10 +15,9 @@
 
 /************************************************************************/
 
-/* v1.9 and beyond */
+/* v2.0 and beyond */
 
-#if (OPAL_MAJOR_VERSION == 1 && OPAL_MINOR_VERSION >= 9) || \
-    (OPAL_MAJOR_VERSION >= 2)
+#if (OPAL_MAJOR_VERSION >= 2)
 
 /* OMPI_ERROR_LOG and friends */
 #  include "opal/util/error.h"
@@ -79,7 +78,7 @@ usnic_compat_proc_name_compare(opal_process_name_t a,
 
 /************************************************************************/
 
-/* v1.7 and v1.8 */
+/* v1.7, v1.8, and v1.10 (there was no v1.9) */
 
 #elif (OPAL_MAJOR_VERSION == 1 && OPAL_MINOR_VERSION >= 7)